summaryrefslogtreecommitdiff
path: root/include/net/inet_frag.h
blob: 5af6eb14c5db1533d559f565deb607934626219d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __NET_FRAG_H__
#define __NET_FRAG_H__

#include <linux/rhashtable-types.h>
#include <linux/completion.h>
#include <linux/in6.h>
#include <linux/rbtree_types.h>
#include <linux/refcount.h>
#include <net/dropreason-core.h>

/* Per netns frag queues directory */
struct fqdir {
	/* sysctls */
	long			high_thresh;
	long			low_thresh;
	int			timeout;
	int			max_dist;
	struct inet_frags	*f;
	struct net		*net;
	bool			dead;

	struct rhashtable       rhashtable ____cacheline_aligned_in_smp;

	/* Keep atomic mem on separate cachelines in structs that include it */
	atomic_long_t		mem ____cacheline_aligned_in_smp;
	struct work_struct	destroy_work;
	struct llist_node	free_list;
};

/**
 * enum: fragment queue flags
 *
 * @INET_FRAG_FIRST_IN: first fragment has arrived
 * @INET_FRAG_LAST_IN: final fragment has arrived
 * @INET_FRAG_COMPLETE: frag queue has been processed and is due for destruction
 * @INET_FRAG_HASH_DEAD: inet_frag_kill() has not removed fq from rhashtable
 * @INET_FRAG_DROP: if skbs must be dropped (instead of being consumed)
 */
enum {
	INET_FRAG_FIRST_IN	= BIT(0),
	INET_FRAG_LAST_IN	= BIT(1),
	INET_FRAG_COMPLETE	= BIT(2),
	INET_FRAG_HASH_DEAD	= BIT(3),
	INET_FRAG_DROP		= BIT(4),
};

struct frag_v4_compare_key {
	__be32		saddr;
	__be32		daddr;
	u32		user;
	u32		vif;
	__be16		id;
	u16		protocol;
};

struct frag_v6_compare_key {
	struct in6_addr	saddr;
	struct in6_addr	daddr;
	u32		user;
	__be32		id;
	u32		iif;
};

/**
 * struct inet_frag_queue - fragment queue
 *
 * @node: rhash node
 * @key: keys identifying this frag.
 * @timer: queue expiration timer
 * @lock: spinlock protecting this frag
 * @refcnt: reference count of the queue
 * @rb_fragments: received fragments rb-tree root
 * @fragments_tail: received fragments tail
 * @last_run_head: the head of the last "run". see ip_fragment.c
 * @stamp: timestamp of the last received fragment
 * @len: total length of the original datagram
 * @meat: length of received fragments so far
 * @tstamp_type: stamp has a mono delivery time (EDT)
 * @flags: fragment queue flags
 * @max_size: maximum received fragment size
 * @fqdir: pointer to struct fqdir
 * @rcu: rcu head for freeing deferall
 */
struct inet_frag_queue {
	struct rhash_head	node;
	union {
		struct frag_v4_compare_key v4;
		struct frag_v6_compare_key v6;
	} key;
	struct timer_list	timer;
	spinlock_t		lock;
	refcount_t		refcnt;
	struct rb_root		rb_fragments;
	struct sk_buff		*fragments_tail;
	struct sk_buff		*last_run_head;
	ktime_t			stamp;
	int			len;
	int			meat;
	u8			tstamp_type;
	__u8			flags;
	u16			max_size;
	struct fqdir		*fqdir;
	struct rcu_head		rcu;
};

struct inet_frags {
	unsigned int		qsize;

	void			(*constructor)(struct inet_frag_queue *q,
					       const void *arg);
	void			(*destructor)(struct inet_frag_queue *);
	void			(*frag_expire)(struct timer_list *t);
	struct kmem_cache	*frags_cachep;
	const char		*frags_cache_name;
	struct rhashtable_params rhash_params;
	refcount_t		refcnt;
	struct completion	completion;
};

int inet_frags_init(struct inet_frags *);
void inet_frags_fini(struct inet_frags *);

int fqdir_init(struct fqdir **fqdirp, struct inet_frags *f, struct net *net);

static inline void fqdir_pre_exit(struct fqdir *fqdir)
{
	/* Prevent creation of new frags.
	 * Pairs with READ_ONCE() in inet_frag_find().
	 */
	WRITE_ONCE(fqdir->high_thresh, 0);

	/* Pairs with READ_ONCE() in inet_frag_kill(), ip_expire()
	 * and ip6frag_expire_frag_queue().
	 */
	WRITE_ONCE(fqdir->dead, true);
}
void fqdir_exit(struct fqdir *fqdir);

void inet_frag_kill(struct inet_frag_queue *q);
void inet_frag_destroy(struct inet_frag_queue *q);
struct inet_frag_queue *inet_frag_find(struct fqdir *fqdir, void *key);

/* Free all skbs in the queue; return the sum of their truesizes. */
unsigned int inet_frag_rbtree_purge(struct rb_root *root,
				    enum skb_drop_reason reason);

static inline void inet_frag_put(struct inet_frag_queue *q)
{
	if (refcount_dec_and_test(&q->refcnt))
		inet_frag_destroy(q);
}

/* Memory Tracking Functions. */

static inline long frag_mem_limit(const struct fqdir *fqdir)
{
	return atomic_long_read(&fqdir->mem);
}

static inline void sub_frag_mem_limit(struct fqdir *fqdir, long val)
{
	atomic_long_sub(val, &fqdir->mem);
}

static inline void add_frag_mem_limit(struct fqdir *fqdir, long val)
{
	atomic_long_add(val, &fqdir->mem);
}

/* RFC 3168 support :
 * We want to check ECN values of all fragments, do detect invalid combinations.
 * In ipq->ecn, we store the OR value of each ip4_frag_ecn() fragment value.
 */
#define	IPFRAG_ECN_NOT_ECT	0x01 /* one frag had ECN_NOT_ECT */
#define	IPFRAG_ECN_ECT_1	0x02 /* one frag had ECN_ECT_1 */
#define	IPFRAG_ECN_ECT_0	0x04 /* one frag had ECN_ECT_0 */
#define	IPFRAG_ECN_CE		0x08 /* one frag had ECN_CE */

extern const u8 ip_frag_ecn_table[16];

/* Return values of inet_frag_queue_insert() */
#define IPFRAG_OK	0
#define IPFRAG_DUP	1
#define IPFRAG_OVERLAP	2
int inet_frag_queue_insert(struct inet_frag_queue *q, struct sk_buff *skb,
			   int offset, int end);
void *inet_frag_reasm_prepare(struct inet_frag_queue *q, struct sk_buff *skb,
			      struct sk_buff *parent);
void inet_frag_reasm_finish(struct inet_frag_queue *q, struct sk_buff *head,
			    void *reasm_data, bool try_coalesce);
struct sk_buff *inet_frag_pull_head(struct inet_frag_queue *q);

#endif